Travelers are often warned against going off alone on dark nights or staying in black rooms, lest the eerie glow of an Umbreon's eight rings be the last thing they ever see, despite the fact that Umbreon are not adept assassins. Although they can sneak around extraordinarily well, they lack a Scyther's claws or even a Weedle's sting; it will typically take several blows for an Umbreon to fell its opponent, unless the target is a human whose pokeballs are dislodged with a single swipe of the paw.
Umbreon may attack without killing in a single strike, like most pokemon which haunt our nightmares, but they do not need to. Invisible except for their rings in darkness, Umbreon are a sturdy pokemon which heal themselves and become even harder to see by stealing the light of the moon. They strike from every angle, their flickering rings the only giveaway to their presence, for they are as silent as they are dark. Trainers have famously described fighting them as like catching Beldum, for the task is equally difficult and requires perfect precision.
And most importantly, Umbreon understand the value of a tactical retreat and of picking one's battles, and although this has been made them ignored by many a trainer or killer, it has allowed them a far greater chance of survival. When faced with a real possibility of defeat, they slink back into the shadows and wait for an easier food source to come by, be it Kirlia, Kadabra, or Man.